Semiconductor Package Assembly for Creepage Control in High-Voltage Packaging
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Solution Overview
Problem
Semiconductor package assemblies for high voltage devices face challenges in meeting minimum creepage and clearance distance requirements due to size constraints, leading to potential reliability failures such as arcing and tracking.
Innovation Solution
Incorporating electric field modulation structures within the molding resin case, specifically a metal shielding plate connected to the bond element, which alters and reduces the electric field between conductive connections, ensuring proper insulation and preventing failures by directing voltage potential to the package edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the package size is reduced to meet higher density electronics requirements, then the package density is improved, but the creepage and clearance distance between conductive parts is reduced below standard requirements
Solution Approach 1:
A resin protrusion is introduced as an intermediary insulating structure between conductive parts (bond element and lead frame). This protrusion extends from the first lead frame side toward the second lead frame side, creating additional physical separation and increasing the creepage distance without increasing the overall package footprint. The resin material acts as a mediator that maintains electrical insulation while allowing compact packaging.
Solution Approach 2:
The solution addresses the two-dimensional planar distance limitation by utilizing the third dimension (vertical height). The resin protrusion extends vertically from the lead frame upward into the package, creating a three-dimensional insulation path. This allows the creepage distance to be increased in the vertical dimension while maintaining a compact horizontal footprint, effectively resolving the contradiction between small package size and adequate creepage distance.
2Reliability
If the creepage and clearance distance is increased to meet standard requirements, then the reliability is improved, but the package size increases
Solution Approach 1:
The insulating structure is segmented into multiple parts: the existing molding resin case and an additional resin protrusion. The protrusion is a separate, localized segment that provides additional creepage distance only where needed between specific conductive elements. This segmented approach allows increased reliability without proportionally increasing the entire package volume, as the protrusion is added only in critical insulation zones.
Solution Approach 2:
Instead of uniformly increasing the package size throughout, the resin protrusion is localized to specific areas where creepage distance enhancement is needed. The protrusion selectively extends from the lead frame in regions adjacent to bond elements or other conductive parts, providing localized insulation enhancement. This maintains compact overall dimensions while achieving adequate creepage distance at critical locations.
3Reliability
If electric field modulation structures are added to suppress arcing and tracking, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The electric field modulation function is merged with the existing molding resin case structure. The resin protrusion is integrated into the package assembly as part of the molding resin, combining the insulation function with the electric field modulation function. This eliminates the need for separate, complex shielding structures, as the resin material itself provides both mechanical support and electric field control through its dielectric properties and geometric configuration.
Solution Approach 2:
The solution changes the geometric parameters of the insulating resin structure by adding a protrusion with specific dimensions and positioning. By adjusting the height, width, and position of the resin protrusion, the electric field distribution is modified to suppress arcing and tracking. This parameter-based approach is simpler than adding complex active shielding structures, as it uses passive geometric modification to achieve field control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The electric field modulation structures effectively limit high electric fields to insulated areas, preventing arcing and tracking, thus enhancing the reliability of semiconductor package assemblies by maintaining proper insulation and preventing contacts with opposite polarity.
Implementation Method 1
electric field modulation structures structured to, during operation of the semiconductor package assembly, alter an electric field created between the first conductive connection and the at least further conductive connection
Implementation Method 2
the electric field modulation structures are manufactured from a metal and in particular are formed as a shielding plate mounted to the first part of the at least one bond element within the molding resin case
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
A semiconductor package assembly is proposed, consisting of a semiconductor package and a molding resin case, the semiconductor package at least comprising a lead frame having a first lead frame side and a second lead frame side opposite to the first lead frame side; a semiconductor die structure having a first die side and a second die side opposite to the first die side, the semiconductor die structure being mounted with its second die side on the first lead frame side of the lead frame, resulting in a first conductive connection; at least one bond element being connected to the first die side of the semiconductor die structure, resulting in at least one further conductive connection; with the molding resin case encapsulating at least the semiconductor die structure, the lead frame and a first part of the at least one bond element connected to the semiconductor die structure, leaving at least the second lead frame side and the other part of the at least one bond element partly exposed, wherein the at least one bond element is provided with electric field modulation structures structured to, during operation of the semiconductor package assembly, alter an electric field created between the first conductive connection and the at least further conductive connection.